Geologic Time Calculations

Francisco C. San Juan, Elizabeth City State University
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Students should learn how to be able to determine radiometric age of earth materials, given the percentages of parent and daughter isotopes. However, many students have problems working with graphs. The first part of the exercise is plotting a simple time-temperature graph, followed by simple questions based on their plotted data.
The second part is a more complicated set of data (% parent/daughter amounts, accompanied with a radioactive decay curve). The students are supposed to determine the age of the based on the given information

Learning Goals

Goal is simple radiometric age calculations using a graph. Skills in getting information from a given graphical plot is something that many students have not mastered yet.

Context for Use

The activity is in conjuntion with problems and exercises in a geologic time chapter. Most of the students are freshmen non-science majors, with low SAT scores. Elizabeth City State University (ECSU) is the smallest constituent institution of the University of North Carolina system and offers only undergraduate degrees except for 3 M.S. programs. ECSU is also a historically black university (HBCU) that caters to the 20 plus surrounding counties in the rural part of northeastern North Carolina.

Description and Teaching Materials

This activity was developed by the author to help students understand the concept of radiometric age dating. The file is in Word format. Activity handout (Microsoft Word 519kB Jun28 06)

Teaching Notes and Tips

The actual age calculations usually caused a lot of problems. A tutorial/instruction or sample calculation might help.

References and Resources

For now, the textbook is a good source of information, aside from class lecture/discussion. This activity was developed to complement the lecture on this topic.